Novel nonaromatic dianhydride and polyimides from tricyclo [4.2.1.02,5 ] nonane-3,4 dimethyl-3,4,7,8-tetracarboxylic acid dianhydride

ABSTRACT

Novel polyimides and molding compositions are prepared from novel tricyclo[4.2.1.0 2 ,5 ] nonane-3,4 dimethyl-3,4,7,8-tetracarboxylic acid dianhydride. The dianhydride is useful for the manufacture of polyimides which are useful as engineering plastics.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of this invention relates to novel nonaromatic dianhydridesand to polyimides and copolyimides prepared from the novel nonaromaticdianhydrides or mixtures of these with other dianhydrides.Tricyclo[4.2.1.0²,5 ]nonane-3,4-dimethyl-3,4,7,8-tetracarboxylic aciddianhydride (I) is a novel compound. I is used to prepare novelpolyimides which are useful in preparing molded articles, fibers,laminates and coatings.

2. Background

British Patent Specification 570,858 discloses various processes formaking fiber forming polymers. The prior art does not disclose orcontemplate I nor the polyimides prepared from I which are useful asmoldings, fibers, laminates and coatings.

The general object of this invention is to provide novel polyimides andcopolyimides based on the new dianhydride I and one or more diaminemoieties. A more specific object of this invention is to providepolyimides from I and aliphatic, cycloaliphatic, araliphatic andaromatic diamine moieties. It is also suitable to use a mixture of I andanother aromatic or aliphatic dianhydrides to manufacture copolyimides.

We have found that novel polyimides can be formed by reacting I withdiamines. I reacts readily with the diamine to form a high molecularweight polyimide. In the novel process both aliphatic and aromaticdiamines can be polymerized with I in the melt to form high molecularweight polyimides and copolyimides.

Our process for the manufacture of the novel polyimides and copolyimidescomprises reacting about equal molar amounts of I with a primary diamineor a mixture of primary diamines. The molecular ratio of I to theprimary diamine may be in the range of 1.2 to 1 preferably in the rangeof 1 to 1. In suitable method, the reaction is conducted as a batchreaction at a temperature of about 130° to 300° C. for a period of about2 to 8 hours in a nitrogen containing organic polar solvent such asN-methyl-2-pyrrolidinone, N,N-dimethylacetamide or pyridine. I can bereplaced partially by another dianhydride either aromatic or aliphatic.

The other dianhydrides are characterized by the following formula:##STR1## wherein R' is a tetravalent organic radical selected from thegroup consisting of aromatic, aliphatic, cycloaliphatic, heterocyclic,combination of aromatic and aliphatic, and substituted groups thereof.However, the preferred dianhydrides are those in which the R' groupshave at least 6 carbon atoms, wherein the 4 carbonyl groups of thedianhydride are each attached to separate carbon atoms and wherein eachpair of carbonyl groups is directly attached to adjacent carbon atoms inthe R' group to provide a 5-membered ring as follows: ##STR2## Thepreferred dianhydrides, as recited above, yield upon reaction with thediamines polyimide structures having outstanding physical properties.Illustrations of dianhydrides suitable for use in the present inventioninclude: pyromellitic dianhydride; 2,3,6,7-naphthalene tetracarboxylicdianhydride; 3,3',4,4-diphenyl tetracarboxylic dianhydride;1,2,5,6-naphthalene tetracarboxylic dianhydride; 1,2,3,4-cyclopentanetetracarboxylic dianhydride; 2,2',3,3'-diphenyl tetracarboxylicdianhydride; 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride;2,3,4,5-pyrrolidine tetracarboxylic dianhydride; 3,4,9,10-perylenetetracarboxylic dianhydride; bis(3,4-dicarboxyphenyl)ether dianhydride;ethylene tetracarboxylic dianhydride;3,3',4,4'-benzophenonetetracarboxylic dianhydride;bis(3,4-dicarboxyphenyl)sulfide dianhydride;bis(3,4-dicarboxyphenyl)sulfone dianhydride;bis(3,4-dicarboxyphenyl)methane dianhydride;1,4,5,8-naphthalenetetracarboxylic dianhydride; tricyclo[4,2,2,0²,5]dec-7-ene-3,4,9,10-tetracarboxylic dianhydride;3,6-ethenohexahydropyromellitic dianhydride;cyclobutane-1,2,3,4-tetracarboxylic dianhydride; and1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride. Thepolycondensation can also be carried out as a continuous process. Thepolycondensation can suitably be carried out at a temperature of 130° C.to 300° C., preferably at a temperature of 180° to 250° C. The novelpolyimides of this invention have the following recurring structurewherein R is a divalent aliphatic or aromatic hydrocarbon radical.##STR3## The radical R may be a divalent aliphatic hydrocarbon of 2 to18 carbon atoms or an aromatic hydrocarbon from 6 to 20 carbon atoms, oran aromatic hydrocarbon radical containing from 6 to 10 carbon atomsjoined directly or by stable linkage comprising --O--, methylene,##STR4## and --S-- radicals. The radical R is derived from aliphatic,araliphatic or cycloaliphatic diamines such as ethylenediamine,propylenediamine, 2,2-dimethylpropylene diamine, tetramethylene diamine,hexamethylene diamine, octamethylene diamine, nonamethylene diamine,decamethylene diamine, dodecamethylene diamine,4,4'-diaminodicyclohexylethane, xylylene diamine andbis(aminomethyl)cyclohexane. Suitable aromatic diamines useful in ourprocess include para- and meta-phenylenediamine, 4,4'-oxydianiline,thiobis(aniline), sulfonylbis(aniline), diaminobenzophenone,methylenebis(aniline), benzidine, 1,5-diaminonaphthalene,oxybis(2-methylaniline), thiobis(2-methylaniline), and the like.Examples of other useful aromatic primary diamines are set out in U.S.Pat. No. 3,494,890 (1970) and U.S. Pat. No. 4,016,140 (1972) bothincorporated herein by reference. The preferred diamines arehexamethylene diamine and dodecamethylene diamine.

In some cases the polyimide may be further polymerized under "solidstate polymerization" conditions. The term solid state polymerizationrefers to chain extensions of polymer particles under conditions wherethe polymer particles retain their solid form and do not become a fluidmass. The solid state polymerization can be carried out below themelting point of the polyimide and can be conducted in several ways.However all techniques require heating the ground or pelletizedpolyimide below the melting point of the polyimide, generally at atemperature of about 175° to 300° C. while either sparging with an inertgas such as nitrogen or operating under vacuum. In cases where thepolyimides and copolyimides have a low melt temperature, they can bepolymerized in the melt under vacuum in thin sections or using thin filmreactors known in the art.

Injection molding of the novel polyimide is accompanied by injecting thepolyimide into a mold maintained at a temperature of about 25° C. to150° C. In this process a 20 second to 1 minute cycle is used with abarrel temperature of about 125° C. to 350° C. The latter will varydepending on the T_(g) of the polymer being molded. The injectionmolding conditions are given in Table 1.

                  TABLE I                                                         ______________________________________                                        Mold Temperature   25 to 150° C.                                       Injection Pressure 15,000 to 19,000 psi and                                                      held for 1 to 3 seconds                                    Back Pressure      100 to 220 psi                                             Cycle Time         25 to 28 seconds                                           Extruder:                                                                     Nozzle Temperature 125° C. to 350° C.                           Barrels:                                                                      Front heated to    125° C. to 350° C.                           Screw:                                                                        20 to 25 revo-                                                                lutions/minute                                                                ______________________________________                                    

The novel polyimides have excellent mechanical and thermal propertiesand can readily be molded into useful articles or formed into fibers,films, laminates or coatings.

Infrared spectra of the polyimides have confirmed the polyimidestructure.

Analysis of the polyimides by thermal gravimetric analysis showsexcellent stability. Glass transition temperature Tg of the polyimidesvaried with the particular diamine used. Values range from a Tg of 65°C. to 115° C.

Diamines with the amino groups attached directly to the aromatic ringare suitably polymerized with I by solution condensation in organicpolar solvents. They include N,N-dimethylacetamide,N-methyl-2-pyrrolidinone, N,N-dimethylformamide, pyridine, and the like.

The following examples illustrate the preferred embodiment of theinvention. It will be understood that the examples are for illustrativepurposes only and do not purport to be wholly definitive with respect toconditions or scope of the invention.

EXAMPLE 1 Synthesis of Tricyclo[4.2.1.0²,5]Nonane-3,4-Dimethyl-3,4,7,8-Tetracarboxylic Acid Dianhydride (I)

I of the following structure: ##STR5## is prepared by aphotocycloaddition reaction between dimethylmaleic anhydride (II) and5-norbornene-2,3-dicarboxylic anhydride (III). To a 500-ml pyrexerlenmeyer flask equipped with a condenser was added 5.0 g (40 mmole) ofII, 6.51 g (40 mmole) of III and 0.3 g of benzophenone. The mixture wasdissolved in 100 ml toluene and exposed to light from a GE sunlamp for64 hours. During this time the insoluble photodimer of II was filteredoff at several intervals. At the end of the irradiation the filtrate wasconcentrated to approximately 50 ml on a rotary evaporator. Iprecipitated and was collected and washed with a small volume of coldtoluene. Approximately one half of II dimerized to the usefultetramethylcyclobutane tetracarboxylic dianhydride.

The yield of I based on the remaining dimethylmaleic anhydride was 30%.Its melting point after recrystallization from acetone is 315°-8° C.(dec.) Anal. Calcd. for C₁₅ H₁₄ O₆ : C, 62.07, H, 4.83. Found: C, 62.35;H, 4.95.

The mass spectrum recorded at a probe temperature of approximately 220°C. is consistent with the proposed configuration for I. A partial listof the ions detected is shown here:

    ______________________________________                                               Mass Ion Identification                                                                           Fragmentation                                      ______________________________________                                                 290    C.sub.15 H.sub.14 O.sub.6                                                                    I.sup.+, molecular ion                                  275    C.sub.14 H.sub.11 O.sub.6                                                                    I--CH.sub.3                                             272    C.sub.15 H.sub.12 O.sub.5                                                                    I--H.sub.2 O                                            262    C.sub.14 H.sub.14 O.sub.5                                                                    I--CO                                                   245    C.sub.14 H.sub.13 O.sub.4                                                                    I--COOH                                                 244    C.sub.14 H.sub.12 O.sub.4                                                                    I--CO--H.sub.2 O                                        234    C.sub.13 H.sub.14 O.sub.4                                                                    I--CO--CO                                      (base peak)                                                                            218    C.sub.13 H.sub.14 O.sub.3l                                                                   I--CO--CO.sub.2                                ______________________________________                                    

EXAMPLE 2

Dianhydride I was crystallized from acetone and dried at 120° C. for 18h. Dodecamethylene diamine (DDA) was distilled under vacuum. DDA, 2.0 g(0.01 mol) was placed in the reaction flask and dissolved in 30 ml ofN-methyl-2-pyrrolidinone (NMP) while purging with nitrogen. Compound I,2.9 g (0.01 mol) was then added all at once and the addition funnel waswashed into the flask with another 15 ml of NMP. The mixture was stirredat 25° C. for 1 h, 100° C. for 1 h, and 150° C. for 1 h. At thistemperature, 20 ml of NMP were distilled off with most of the waterbyproduct. The solution which at this point became viscous was heated at250° C. for 3 h. After cooling to 25° C. the polymer solution was mixedwith water in a blender. The polyimide was filtered, washed with waterand dried in a vacuum oven at 150° C. for 20 h. Nitrogen Analysis:Calcd. for C₂₇ H₃₈ N₂ O₄ : 6.2%. Found: 6.0%.

Measurement of the inherent viscosity (I.V.) for this polymer and allpolymers in the following examples was carried out on a solution made bydissolving 0.1 g of the polymer in 25 ml of a 60/40 mixture ofphenol/tetrachloroethane at 130° C. then cooling to 30° C., thetemperature at which the measurement was made. I.V. for the polyimide ofExample 2 was 0.92 dl/g.

EXAMPLE 3

Another reaction was carried out between I and DDA as in Example 2. Thepolyimide formed had an I.V. of 0.32, and a nitrogen content of 6.4%. Amolded specimen had a Tg of 68° C. and ultimate tensile strength of 5220psi.

EXAMPLE 4

Using 4.35 g (0.015 mol) of I and 1.74 g (0.015 mol) of hexamethylenediamine in 60 ml of NMP, a polyimide was prepared according to Example2. Nitrogen Analysis: Calcd. for C₂₁ H₂₆ N₂ O₄ : 7.7%. Found: 8.1%. Thepolyimide had an I.V. of 0.32. A molded specimen showed the followingproperties: Tg, 112° C.; yield tensile strength, 8720 psi; ultimatetensile strength, 7200 psi; tensile impact strength, 17 ft-lbs/in² ; and% elongation, 70.

We claim:
 1. A polyimide consisting essentially of the followingrecurring structure: ##STR6## wherein R is a divalent aliphatic,cycloaliphatic, araliphatic or aromatic hydrocarbon radical.
 2. Thepolyimide of claim 1 wherein R is an aliphatic hydrocarbon from 2 to 18carbon atoms.
 3. The polyimide of claim 1 wherein R is an aromatichydrocarbon from 6 to 20 carbon atoms.
 4. The polyimide of claim 1wherein the aromatic hydrocarbon radical contains from 6 to 10 carbonatoms joined directly or by stable linkage selected from the groupconsisting essentially of --O--, methylene, ##STR7## radicals.
 5. Thepolyimide of claim 1 wherein the polyimide is in the form of a moldedobject.
 6. The polyimide of claim 1 wherein the polyimide is in the formof a fiber.
 7. The polyimide of claim 1 wherein the polyimide is in theform of a film.
 8. The polyimide of claim 1 wherein the polyimide is inthe form of a metal coating suitable for electrical service.
 9. Apolyimide consisting essentially of the following recurring structure:##STR8##
 10. A polyimide of claim 9 wherein the polyimide is in the formof a molded object.
 11. The polyimide of claim 9 wherein the polyimideis in the form of a fiber.
 12. The polyimide of claim 9 wherein thepolyimide is in the form of a film.
 13. A polyimide consistingessentially of the following recurring structure: ##STR9##
 14. Apolyimide of claim 13 wherein the polyimide is in the form of a moldedobject.
 15. The polyimide of claim 13 wherein the polyimide is in theform of a fiber.
 16. The polyimide of claim 13 wherein the polyimide isin the form of a film.
 17. A copolyimide consisting essentially of thefollowing recurring structure ##STR10## wherein R₁ and R₂ are differentdivalent aliphatic, cycloaliphatic, araliphatic or aromatic hydrocarbonradicals.
 18. The copolyimide of claim 17 wherein R₁ and R₂ arealiphatic hydrocarbons from 2 to 18 carbon atoms.
 19. The copolyimide ofclaim 17 wherein R₁ and R₂ are aromatic hydrocarbons from 6 to 20 carbonatoms.
 20. The copolyimide of claim 17 wherein the polyimide is in theform of a molded object.
 21. The copolyimide of claim 20 wherein thearomatic hydrocarbon radicals contain from 6 to 10 carbon atoms joineddirectly or by stable linkage selected from the group consistingessentially of --O--, methylene, ##STR11## and --S-- radicals.
 22. Thecopolyimide of claim 17 wherein the polyimide is in the form of a fiber.23. The copolyimide of claim 17 wherein the polyimide is in the form ofa film.
 24. A copolyimide consisting essentially of the followingrecurring structure: ##STR12## wherein X is a divalent hydrocarbonradical and X' is a tetravalent hydrocarbon radical.
 25. The copolyimideof claim 24 wherein X and X' are aliphatic hydrocarbons from 2 to 18carbon atoms.
 26. The copolyimide of claim 24 wherein X and X' arearomatic hydrocarbons of 6 to 20 carbon atoms.